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Over the last
5-6 years, a severe haemorrhagic disease of veal calves has been reported in North
America. Since that time, a haemorrhagic and fatal syndrome has been reported in adult
cattle in the U.K. In both cases, isolates of BVDVnc have been recovered in high titre
from tissues of infected animals. American researchers suggest that the BVDV isolates from
their cases are different from typical BVDV, when defined by genome analysis, and so they
suggest that the viruses responsible for severe haemorrhagic disease are grouped as BVDV
Group 2. Most isolates from Group 2 are non-cytopathogenic. It is presently unclear what
importance this group has in the U.K. or elsewhere in Europe. |